A properly built house offers protection against the weather and provides structural stability. Floors may be concrete slab, suspended wood, or steel joist systems. Walls may be framed using wood, wood structural panels, steel, structural masonry, conventional concrete, insulating concrete forms, rammed earth, or straw bales, and include openings. Types of framing that are used to construct houses include platform, balloon, and panelized framing. A roof may be constructed using traditional stick framing, prefabricated trusses, or steel components. A home inspector must have a basic understanding of how a house is built in order to detect deviations from accepted building practices and codes.